Low power consumption is an increasingly important parameter for microcontroller systems. The active power consumption in a microcontroller system is normally dominated by switching activity in the circuit and is proportional to the clock frequency applied to digital logic. Analog modules also contribute a substantially fixed current consumption, which can dominate at low frequencies or in low-power modes.
Conventional power reduction solutions for saving power in a microcontroller require that the clock to the Central Processing Unit (CPU) or peripheral modules be switched off, typically by implementing one or more sleep modes in the microcontroller. Microcontroller systems may require a number of internal calibration values. For microcontroller systems with one or more sleep modes, the number of internal calibration values rises. These calibration values are typically frozen and defined at the design level.